In recent years, a VCSEL (Vertical Cavity Surface Emitting Laser) device has been proposed because of a surface-mount compatibility, power saving or cost reduction. Incidentally, with increases in communication capacity, an optical communication apparatus using a laser as a light source performs multiplex communication by introducing a plurality of laser beams having different wavelengths into a single optical fiber.
To comply with the multiplex communication requirements, according to Japanese Patent Laid-Open Nos. 2007-173394, 2006-073965, and 06-097578, multiwavelength laser devices that can emit a plurality of laser beams having different wavelengths are disclosed. The multiwavelength laser device is provided with the number of light emission portions equivalent to the number of wavelengths to be used. A plurality of desired laser beams having different wavelengths can be generated by resonating a light in the light emitting portions.
Like this, since the number of light emitting portions equivalent to the number of wavelengths to be used is provided in the multiwavelength laser devices, electrodes are provided on each light emitting portion for power feeding. Further, such a multiwavelength laser device for generating laser beams having different wavelengths has a plurality of mirror layers therein. Therefore, the multiwavelength laser device has a complicate internal structure as compared to a single-wavelength laser device. For this reason, according to JP-A-2006-073965, electrodes are provided at the top and bottom of the multiwavelength laser device.
However, according to JP-A-2006-073965, since a plurality of mirror layers having high electric resistances intervene between the electrodes of the top and bottom of the device, the electric resistance between the electrodes may increase, which leads to high power consumption of the multiwavelength laser device.